期刊
ACS APPLIED MATERIALS & INTERFACES
卷 6, 期 10, 页码 7070-7075出版社
AMER CHEMICAL SOC
DOI: 10.1021/am502053d
关键词
electrochemical aptasensor; cucurbit[7]uril; DNA ligase; exonuclease III; thrombin
资金
- National Natural Science Foundation of China [31200745, 21235003]
- Innovation Foundation of Shanghai University [sdcx2012036]
- Shanghai Science and Technology Committee [11DZ2272100]
In this paper, we have proposed a new electrochemical aptasensor based on a novel ligase-assisted Exo III-catalyzed degradation reaction (LAECDR), which consists of DNA ligase-catalyzed ligation of thrombin-binding aptamer (TBA) with an extension strand (E-strand) and Exo III-catalyzed selective degradation of probe DNA, by using an improved target-induced strand displacement strategy. As a result of LAECDR, methylene blue (MB)-labeled mononucleotides can be released from the 3'-terminal of probe DNA and captured by cucurbit[7]uril-functionalized electrode to induce noticeable electrochemical response. Nevertheless, in the presence of the target protein, thrombin, the TBA that is partially complementary to probe DNA is preferentially binding with the target protein, thereby inhibiting LAECDR from taking place. The remaining intact probe DNA will prevent the terminal-attached MB from approaching to the electrode surface due to strong electrostatic repulsion, so the electrochemical response will be changed by thrombin. By tracing the electrochemical response of adsorbed MB, our aptasensor can exhibit high sensitivity for thrombin detection with a wide linear range from 100 fM to 1 nM and an extremely low detection limit of 33 fM, which can also easily distinguish thrombin in the complex serum samples with high specificity. Therefore, our aptasensor might have great potential in clinical applications in the future.
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